Disturbance of sympathetic cardiovascular regulation is involved in CFS

Wyller VB, Saul JP, Walloe L, Thaulow E "...our results suggest that CFS patients suffer from a more comprehensive disturbance of sympathetic cardiovascular regulation than previously acknowledged, supporting the hypothesis that dysautonomia may be a central etiologic component of CFS (Freeman and Komaroff 1997). Specifically, the sympathetic nervous system is more activated at rest, and seems to have an enhanced response to orthostatic stress, but has a reduced response to the addition of isometric exercise. These abnormalities may account for the high prevalence of orthostatic symptoms among CFS patients.